Power battery pack is responsible for storing and supplying power. In use, it is necessary to acquire a power supply voltage of the power battery pack to monitor whether the power supply voltage of the power battery pack has reached a standard voltage in real time, so as to reduce the risk of the power supply from the power battery pack.
At present, in a battery high voltage sampling circuit, the power battery pack and a sampling unit are usually set to not be connected to a common ground. Specifically, it means that positive and negative electrodes of the power battery pack are grounded at a high voltage, while the sampling unit is grounded at a low voltage. In order to isolate a high voltage ground signal of the power battery pack from interfering with a sampled signal of the sampling unit, an insolation unit may be additionally disposed after the sampling unit.
However, the inventor of the application has discovered that the existing insolation unit may further introduce a new interference signal while isolating the high voltage ground signal of the power battery pack, which results in a decrease in the accuracy of the sampled signal.